arch/mips/lasat/interrupt.c

   1 /*
   2  * Carsten Langgaard, carstenl@mips.com
   3  * Copyright (C) 1999,2000 MIPS Technologies, Inc.  All rights reserved.
   4  *
   5  *  This program is free software; you can distribute it and/or modify it
   6  *  under the terms of the GNU General Public License (Version 2) as
   7  *  published by the Free Software Foundation.
   8  *
   9  *  This program is distributed in the hope it will be useful, but WITHOUT
  10  *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  *  for more details.
  13  *
  14  *  You should have received a copy of the GNU General Public License along
  15  *  with this program; if not, write to the Free Software Foundation, Inc.,
  16  *  59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
  17  *
  18  * Routines for generic manipulation of the interrupts found on the
  19  * Lasat boards.
  20  */
  21 #include <linux/init.h>
  22 #include <linux/sched.h>
  23 #include <linux/slab.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/kernel_stat.h>
  26
  27 #include <asm/bootinfo.h>
  28 #include <asm/irq.h>
  29 #include <asm/lasat/lasatint.h>
  30 #include <asm/gdb-stub.h>
  31
  32 static volatile int *lasat_int_status = NULL;
  33 static volatile int *lasat_int_mask = NULL;
  34 static volatile int lasat_int_mask_shift;
  35
  36 extern asmlinkage void lasatIRQ(void);
  37
  38 void disable_lasat_irq(unsigned int irq_nr)
  39 {
  40         unsigned long flags;
  41
  42         local_irq_save(flags);
  43         *lasat_int_mask &= ~(1 << irq_nr) << lasat_int_mask_shift;
  44         local_irq_restore(flags);
  45 }
  46
  47 void enable_lasat_irq(unsigned int irq_nr)
  48 {
  49         unsigned long flags;
  50
  51         local_irq_save(flags);
  52         *lasat_int_mask |= (1 << irq_nr) << lasat_int_mask_shift;
  53         local_irq_restore(flags);
  54 }
  55
  56 static unsigned int startup_lasat_irq(unsigned int irq)
  57 {
  58         enable_lasat_irq(irq);
  59
  60         return 0; /* never anything pending */
  61 }
  62
  63 #define shutdown_lasat_irq      disable_lasat_irq
  64
  65 #define mask_and_ack_lasat_irq disable_lasat_irq
  66
  67 static void end_lasat_irq(unsigned int irq)
  68 {
  69         if (!(irq_desc[irq].status & (IRQ_DISABLED|IRQ_INPROGRESS)))
  70                 enable_lasat_irq(irq);
  71 }
  72
  73 static struct hw_interrupt_type lasat_irq_type = {
  74         "Lasat",
  75         startup_lasat_irq,
  76         shutdown_lasat_irq,
  77         enable_lasat_irq,
  78         disable_lasat_irq,
  79         mask_and_ack_lasat_irq,
  80         end_lasat_irq,
  81         NULL
  82 };
  83
  84 static inline int ls1bit32(unsigned int x)
  85 {
  86         int b = 31, s;
  87
  88         s = 16; if (x << 16 == 0) s = 0; b -= s; x <<= s;
  89         s =  8; if (x <<  8 == 0) s = 0; b -= s; x <<= s;
  90         s =  4; if (x <<  4 == 0) s = 0; b -= s; x <<= s;
  91         s =  2; if (x <<  2 == 0) s = 0; b -= s; x <<= s;
  92         s =  1; if (x <<  1 == 0) s = 0; b -= s;
  93
  94         return b;
  95 }
  96
  97 static unsigned long (* get_int_status)(void);
  98
  99 static unsigned long get_int_status_100(void)
 100 {
 101         return *lasat_int_status & *lasat_int_mask;
 102 }
 103
 104 static unsigned long get_int_status_200(void)
 105 {
 106         unsigned long int_status;
 107
 108         int_status = *lasat_int_status;
 109         int_status &= (int_status >> LASATINT_MASK_SHIFT_200) & 0xffff;
 110         return int_status;
 111 }
 112
 113 void lasat_hw0_irqdispatch(struct pt_regs *regs)
 114 {
 115         unsigned long int_status;
 116         int irq;
 117
 118         int_status = get_int_status();
 119
 120         /* if int_status == 0, then the interrupt has already been cleared */
 121         if (int_status) {
 122                 irq = ls1bit32(int_status);
 123
 124                 do_IRQ(irq, regs);
 125         }
 126 }
 127
 128 void __init arch_init_irq(void)
 129 {
 130         int i;
 131
 132         switch (mips_machtype) {
 133         case MACH_LASAT_100:
 134                 lasat_int_status = (void *)LASAT_INT_STATUS_REG_100;
 135                 lasat_int_mask = (void *)LASAT_INT_MASK_REG_100;
 136                 lasat_int_mask_shift = LASATINT_MASK_SHIFT_100;
 137                 get_int_status = get_int_status_100;
 138                 *lasat_int_mask = 0;
 139                 break;
 140         case MACH_LASAT_200:
 141                 lasat_int_status = (void *)LASAT_INT_STATUS_REG_200;
 142                 lasat_int_mask = (void *)LASAT_INT_MASK_REG_200;
 143                 lasat_int_mask_shift = LASATINT_MASK_SHIFT_200;
 144                 get_int_status = get_int_status_200;
 145                 *lasat_int_mask &= 0xffff;
 146                 break;
 147         default:
 148                 panic("arch_init_irq: mips_machtype incorrect");
 149         }
 150
 151         /* Now safe to set the exception vector. */
 152         set_except_vector(0, lasatIRQ);
 153
 154         for (i = 0; i <= LASATINT_END; i++) {
 155                 irq_desc[i].status      = IRQ_DISABLED;
 156                 irq_desc[i].action      = 0;
 157                 irq_desc[i].depth       = 1;
 158                 irq_desc[i].handler     = &lasat_irq_type;
 159         }
 160 }